During the next year, we plan to attempt to: 1. further characterize the large antigen-associated protein kinase activity and assess its role in T antigen-DNA binding at specific sites on the viral genome; 2. search for additional T antigen-associated biochemical activities; 3. further characterize the effects of microinjected anti-T IgG on T antigen function in vivo; 4. attempt to further characterize the nature of the SV80 T antigen binding sequences in viral DNA; 5. pursue an analysis of the structure of two "middle size" and one "very small" (8K) T antigen in SV80 cells; and 6. improve the yield of large T antigen from SV80 cells during the purification procedure.